Duplicating machine



Jan. 15, 1935. J, BRASSEUR 1,987,923

DUPLICATING MACHINE Filed May 2'7, 1932 3 Sheets-Sheet 2 J/ wasJ/jraasew Jan. 15, 1935. E. J. BRASSEUR 1,987,923

DUPLICATING MACHINE Filed May 27, 1952 5 Sheets-Sheet 3IIIIIIIIIIIIIIIIII, 'IIIIIIIIIIIIIIIIIIIIII/llflIIlIIIIIIIlIIIIIIIl/IIIII!IIIlIIIIIlllIIIllIIII/IIIIIIIIIIW PatentedJan. 15, 1935 UNITED STATES PATENT OFFICE A. B. Dick Company, Chicago,

tion of Illinois 111., acor'pora- Application May :1, 1m, Serial No.01am 6 Claims. (cam-us) This invention relates to duplicating machinesand the like, and more particularly stencil duplicating machines whereina sheet of paper fed into the machine is frictionally enaged between therotatable drum and an impression roller so as to be drawn through themachine in close engagement with the drum and to receive an impressionfrom the stencil thereon. After passing through the printing couple ofthe machine, the impression sheet is diverted from the path of the drumand forwarded to a receiving device, such as a tray, in which thesuccessive sheets are delivered in a pile or stack. To divert the sheetfrom the 13 drum and overcome its natural tendency to adhere to thestencil, it has heretofore'been the practice to engage the edges of thesheet under stripping fingers arranged close to the periphery of thedrum adjacent the ends thereof, and

having a difierent curvature of greater radius than the drum. Thesefingers lead the forward corners of the sheet away from the drum afterpassing through the printing couple, and in conjunction with suitableguides cause its leading edge to follow a path substantially tangent tothe drum surface.

Such devices are quite effective in the stripping of sheets of averagewidth, but considerable difificulty has been experienced in mag chineshaving long drums, such as are used in the printing of the wider sheets,caused by the adherence of the central portion of the sheet which pullsthe edges thereof from under the strippers. This trouble is particularlymarked 86 in the use of thin sheets, or with thick, tacky inks, and isaccentuated when the machine is cold. When it occurs, the sheet crumplesand winds around the drum, necessitating stopping the feed and clearingaway the damaged sheet 40 or sheets, which leads to much annoyance andloss of time and paper. 1

One of the objects of this invention is to provide a duplicating machinein which these difliculties are avoided'and bywhich sheets of any widthare eifectively stripped from the drum regardless of their width andstiilnesaof the character of the ink, the temperature, or any othercondition of operation.

Another object of the invention is to provide stripping means forduplicating machines of the character designated, by which each sheet ispositively deflected away from thestencil drum.

across the entire width of its leading edge at the 55 proper time in thecycle of the machine.

Another object of the invention is to provide a stripping device inwhichthe sheet shall be separated from the drum and stencil by the force ofcompressed air, discharged in jets ar- 80 ranged in a row extendingacross theentire stripping is insured.

Other objects of the invention will appear from the followingdescription, taken in connection with the drawings, which form a part ofthis specification and in which:

Fig. 1 is a perspective view of part of the delivery end of aduplicating machine constructed in accordance with the invention, partlybroken away to show certain features of the structure;

Fig. 2 is a view, partially in end elevation and partially inlongitudinal section, through the duplicating machine shown in Fig. 1;

- Fig. 3 is afragmentary detail view of the stencil clamping. bar of themachine, cut away to show the manifold construction;

Fig. 4 is an end elevation of the stencil carrying drum, showing thesupports therefore and Fig. 6 is a perspective viewof the "drumsupporting bearing member.

Referring to the drawings, at 10 is indicated.

generally a rotary duplicating machine having side frame members such as11, between which a stencil carrying cylinder or drum 12 is rotatablymounted on journal members or trunnions 13 supported in the framemembers. The drum 12 may be of the well known construction comprisingend portions or heads 14 and a perforated, stencil carrying portion 15formed as a segment of a cylinder, and the length of the drum betweenthe heads may be suitable for use with sheets of any desired width, thepresent invention being particularly well adapted for use with the widersheet. An impression roller 16 is rotatably mounted between the framemembers 11 beneath the drum 12, and is adapted to cooperate with thedrum in the well'known manner to form "the printing couple of themachine. The cylindrical portion 15 of the drum is perforated with alarge number of small closely spaced holes 17 through which ink may passfrom the interior of the drum to an ink pad 18 mounted on the surface15, and over which a stencil 19 is stretched as is well understood. Whenthe drum is rotated and a sheet of paper or other suitable impressionmaterial 20 is with the stencil 19, an impression of the matter written,drawn, or typed on the stencil is formed on said sheet in a manner wellunderstood in the art to which this invention relates.

The ink pad 18 is provided at its ends with suitable means such as rods21, the ends of which may be removably engaged in holes or sockets (notshown) provided in the heads 14, or in suitable tensioning devicesinside the stencil carrying portion to stretch the pad around thesurface 15. The stencil 19 is provided at its head end with a reinforcedstrip or stub member having the usual button holes 22 which are engagedwith pins 23 on a bar member or strap 24 extending across the drumbetween the heads 14. A clamping abutment 26 is provided at the edge ofthe surface 15, and the stencil 19 is stretched over this abutment andaround the drum in close contact with the pad 18,'its other end passingover a similar clamping abutment 27 at the other end of the surface andbeing secured thereto by a clamping bar 28 having pivoted arms 29 whichare urged by suitable springs 31 to maintain the bar in clampingengagement with the abutment.

A clamping member 32 is also provided for cooperation with the abutment26 for clamping the stencil and the pad at the leading edge thereof. Asshown, this member is in the form of a movable bar provided withradially disposed integral end arms 33, having hubs 34 which are mountedto pivot about the axis of rotation of the drum. Suitable toggle means36 is provided between each of the arms 33 and the adjacent drum head 14by which the mem ber 32 may be swung toward the abutment 26 to clamp thepad and stencil there-between with a considerable pressure, and to lockthe member 32 in clamped position. The member 32 is provided with asurface 37 which forms a continuation of the cylindrical surface 15, andit is made hollow with closed ends, as shown, for a purpose to bedescribed.

The journal member 13 has a bearing portion '41 on which a drum bearing42 is mounted to rotate, and this drum bearing is formed with a portion43 of reduced diameter defining a bearing surface 44 on which the hub 34is mounted to rotate with the drum and also to pivot with respect.thereto. The bearing trunnion 13 is also provided near its end with atapered shoulder portion 46 which is drawn into cooperative engagementwith a corresponding surface formed in the hub 34 by a nut on a threadedextension 47 of the trunnion. This construction retains the hub 42 inproper axial position and also provides an air-tight seal between thetrunnion and the hub 34. A pulley 48 is also journaled on the member 13adjacent the side frame member, its hub 49 being axially spaced from thehub 42 by a sleeve 51 surrounding the member 13. The pulley 48 may bedriven by a belt 52 from a motor or-other suitable source of power, andany convenient means may be provided for detachably connecting thepulley to the drum in driving relation. As motors and clutch devicessuitable for such drives are well known, and as they form no part ofthis invention, the specific construction is not illustrated.

The delivery side of the machine is provided with suitable sheetforwarding means. adapted to advance the impression sheets from theprinting couple. As shown, this comprisesa pair of friction rollers suchas 53, splined to and driven from a shaft 54 mounted in suitablebearings in through the printing couple, to

, surface of the member 32 and may the side frame members and which maybe driven from the machine in any convenient manner, not shown. There isone of the rollers 53 at each side of the machine and the hub of each ofthese rollers is disposed between arms 56 and 57 of a forked yoke member58, the shaft 54 passing through holes provided in the arms. The member58 is mounted on a crossbar 59 secured to and between the frame members11, and it may be adjustably secured thereon by locking means such as ascrew 61. In this way the rollers 53 may be adjusted laterally of themachine to the width of the sheets being printed, so that the edgeportions of each sheet pass over the rollers. The outer arm 57 of eachyoke 58 is extended upwardly and pivotally supports, as at 62, a lever63 having a pin 64 on which a roller 66 is journaled to rotate incontact with the edge portion of the sheet above the roller 53. Asuitable spring 6'7, connected between lever 63 and arm 57 holds theroller 66 in engagement with the sheet, and the sheet in turn infrictional engagement with the roller 53, so that this driven roller 53operates to positively withdraw the sheet advanced by the printingcouple. Suitable rails 68, carried by arms 69 which are secured to andadjustable on the crossbar 59, support the central portion of the sheetbetween the forwarding rollers 53, and

preferably extend forwardly and downwardly from adjacent the impressionroller 16.

Secured to and extending rearwardly from each of the arms 57, in closeproximity to the periphery of the drum head 14 is a stripper member orarm 71, which terminates at the feed end of the machine just in front ofthe crotch of the printing couple (not shown), and at its rear end justin advance of the crotch between the forwarding rollers 53 and 66. Infeeding the sheet tothe printing couple, its side edges are engagedbeneath the members 71, and as is well known, these members move theleading corners of the sheet tangentially away from the cylindrical drumsurface after passing strip the printed sheet from the stencil. However,in the practical operation of such machines, it frequently happens thatthe adherence between the central portions of the stencil and theprinted sheet, particularly at the leading edge thereof, is sufficientto carry the central portion of the sheet around the drum with thestencil, drawing the edges of the sheet laterally from under thestrippers '71. When this happens, the sheet so carried around iscrumpled and spoiled, and in turn blocks the passage of succeedingsheets, so that frequently a number of sheets are wasted before theoperator can stop the machine, which must then be cleared and restarted.

The pneumatic stripping means of this invention'is carried by the drumand is operative on the entire width of the printed sheet along theleading edge thereof to obviate the difficulties described. As shown inthe drawings, it comprises a manifold '12, formed by the hollow clampingmember 32, and a number of small holes or ports 73 extending in a rowalong the member 32 and terminating in the surface 3'] thereof, whichcommunicate 'with the manifold. These ports are placed close to theclamping be disposed substantially radially of the drum. The manifold issupplied with air under pressure from any convenient source (not shown),which may be a compressor driven from the machine or tling groove 81,and the port 83.

from a separate motor mounted on or adjacent the machine. Such source ofcompressed air is connected to a duct or passage 76 provided in one ofthe side frames 11, and which terminates in a port 77 at the journalmember 13. This journal member is provided with a longitudinal passage78 having a port 79 at its outer end adapted to register with the port77, whereby the passage 76 is in communication with the passage 78. Theinner end of the bearing member 13 is provided with throttling meanscomprising a shallow circumferential groove 81, formed in the reducedbearing portion 44 and arranged in the plane of rotation of the hub 34,which groove is connected to the passage 78 through a metering port 82.The hub 34 is provided with a port 83 in registry with the groove 81,which port communicates through a conduit 84, carried by or formed inthe end arm 33, with the manifold 72.

The ports 82 and 83 are of substantially the same size, and are adaptedto come into aligned position once during each revolution of the drum.The number 13 is retained in position with the ports 77 and '79 inregistry by locking means, such as a pin 86, and the angular relation ofthe ports 82 and 7'7 about the axis of rotation is such that the ports82 and 83 come into alignment just as the leading edge of the sheetemerges from the crotch of the printing couple. I

It will be seen from the above description, that in operation there is asmall continuous flow of air under pressure through duct 76 and passage78 to conduit 84 and the manifold 72, which flow takes place throughport 82, throt- Groove 81, however, restricts this flow and only permitsthe by-passing or leakage of suflicient air to prevent the operation ofthe pressure relief means usually provided on the compressor or othersource of pressure air, and therefore acts as a pressure reducing meansto keep the air pressure in the manifold '72 at a low point during themajor portion of the revolution of the drum. As the impression sheetemerges from the printing couple, however, there is a short interval inwhich ports 82 and 83 are aligned to form a direct and unthrottledconnection, which permits a sudden and considerable increase of pressurein the manifold and a corresponding increase in the discharge of airthrough the ports 73. This air is discharged between the drum surfaceand sheet 20, and forces or blows the leading edge of the sheet awayfrom the drum as clearly shown in Fig. 2, stripping it completely fromthe stencil across its entire width adjacent the leading edge. Shortlyafter stripping is thus commenced the corners of the sheet are engagedbetween the rollers 53 and 66, which forward it to the receiving devicein the usual way.

It will be evident that this invention provides means in which the sheetis separated from the stencil not only at its side edges but across itsentire. width, thus effectively preventing adherence at the centralportion of the leading edge from carrying the sheet around the drum. Itwill also be seen that as the stripping air is discharged between thesheet and the drum, the action is independent of the width or stiffnessof the sheet, and the adhesiveness of the stencil, and operates as wellwith wide, thin sheets and with cold, tacky inks as it does under themore favorable operating conditions.

While a specific embodiment of the invention has been herein described,which is deemed to be new and advantageous and may be specificallyclaimed, it is not to be understood that the invention is limited to theexact details of the construction, as it will be apparent that changesmay be made therein without departing from the spirit or scope of theinvention.

Having thus described the invention, what is claimed and desired to beprotected by Letters Patent is:

1. In a duplicating machine having a stencil carrying drum provided withan axially disposed bearing, a discharge manifold carried by the drum, aconduit connecting the manifold to the bearing and terminating in a portin the bearing surface, a fixed journal cooperating with said bearinghaving a circumferential groove in registry with said port, and meansincluding a passage in said journal communicating with said port tosupply air under pressure to said manifold.

2. In a duplicating machine having a rotary stencil carrying drum, adischarge manifold carried by said drum, a bearing for said drum, 2.metering port carried by said bearing and connected to said manifold,means including a conduit adapted to supply air under pressure to themanifold through said port during a portion of the drum rotation, andflow restricting means adapted to supply a lesser quantity of air tosaid port throughout the remainder of the drum rotation.

3. In a duplicating machine having a printing element rotatable toadvance an impression sheet, a manifold adapted to continuouslydischarge air under pressure between the printing element and theimpression sheet, and means including registrable ports to supply airunder increased pressure periodically to said manifold.

4. In a duplicating machine having a printing element rotatable toadvance an impression sheet, a manifold adapted to discharge air underpressure between the printing element and the impression sheet, andmeans to supply air under pressure to said manifold, said meansincluding a throttlingpassage and means to bypass said passage in timedrelation to the printing element.

5. In a duplicating machine having a printing element with an inkedsurface and rotatable toadvance an impression sheet in contacttherewith, means carriedby said printing elementto continuouslydischarge air at the surface of said element, and means to increase thepressure of the discharged air to strip the impression sheet from saidinked surface.

6. In a duplicating machine having a stencil carrying drum, a stencilclamp pivotally mounted on said drum and forming a part of the drumsurface, air discharge ports in said drum surface portion of 'thestencil clamp, means to continuously discharge air at low pressurethrough said ports, and means controlled by rotation of the drum toperiodically increase the pressure of the air discharged.

ERNEST J. BRASSEUR.

